A method for forming a semiconductor device structure is provided. The method includes providing a substrate and an insulating layer over the substrate. The insulating layer has a trench partially exposing the substrate. The method includes forming a gate dielectric layer over an inner wall and a bottom of the trench. The method includes forming a mask layer over the gate dielectric layer over the bottom. The method includes removing the gate dielectric layer over the inner wall. The method includes removing the mask layer. The method includes forming a gate electrode in the trench.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for forming a semiconductor device structure, comprising: providing a substrate and an insulating layer over the substrate, wherein the insulating layer has a trench partially exposing the substrate; forming a gate dielectric layer over an inner wall and a bottom of the trench; depositing a mask material layer over the gate dielectric layer; performing an oxidation process over the mask material layer to oxidize the mask material layer over the inner wall, wherein an upper portion of the mask material layer over the bottom is oxidized by the oxidation process, and a lower portion of the mask material layer over the bottom is not oxidized by the oxidation process; removing the mask material layer, which is oxidized, wherein the mask material layer, which is not oxidized, is remained and forms a mask layer; removing the gate dielectric layer over the inner wall; removing the mask layer; and forming a gate electrode in the trench.
2. The method for forming the semiconductor device structure as claimed in claim 1 , wherein the mask material layer is made of a metal nitride material.
3. The method for forming the semiconductor device structure as claimed in claim 1 , wherein the oxidation process comprises a plasma oxidation process.
4. The method for forming the semiconductor device structure as claimed in claim 1 , wherein the lower portion is thicker than the gate dielectric layer over the bottom.
5. The method for forming the semiconductor device structure as claimed in claim 1 , wherein the removing of the gate dielectric layer over the inner wall further comprises: removing a portion of the gate dielectric layer over the bottom, wherein the portion is adjacent to and not covered by the mask layer.
6. The method for forming the semiconductor device structure as claimed in claim 1 , wherein the gate dielectric layer has a first dielectric constant greater than a second dielectric constant of silicon dioxide.
7. The method for forming the semiconductor device structure as claimed in claim 1 , further comprising: after removing the mask layer and before forming the gate electrode in the trench, forming a work function layer over the inner wall and the gate dielectric layer, wherein the gate electrode is formed in the trench and over the work function layer.
8. A method for forming a semiconductor device structure, comprising: providing a substrate and an insulating layer over the substrate, wherein the substrate has a fin structure, and the insulating layer has a trench extending across and partially exposing the fin structure; forming a gate dielectric layer in the trench, wherein the gate dielectric layer covers an inner wall of the trench and the fin structure exposed by the trench; depositing a mask material layer over the gate dielectric layer; performing an oxidation process over the mask material layer to oxidize the mask material layer over the inner wall, wherein an upper portion of the mask material layer over the gate dielectric layer covering the fin structure is oxidized by the oxidation process, and a lower portion of the mask material layer over the gate dielectric layer covering the fin structure is not oxidized by the oxidation process; removing the mask material layer, which is oxidized, wherein the lower portion of the mask material layer is remained and forms a mask layer; removing the gate dielectric layer over the inner wall; removing the mask layer; and forming a gate electrode in the trench and over the gate dielectric layer.
9. The method for forming the semiconductor device structure as claimed in claim 8 , wherein the oxidation process comprises a plasma oxidation process without bias voltage.
10. The method for forming the semiconductor device structure as claimed in claim 8 , further comprising: performing an oxidization process over the fin structure exposed by the trench before forming the gate dielectric layer in the trench.
11. The method for forming the semiconductor device structure as claimed in claim 8 , wherein a peripheral portion of the gate dielectric layer remains between the mask layer and the inner wall after removing the gate dielectric layer over the inner wall.
12. The method for forming the semiconductor device structure as claimed in claim 8 , wherein the lower portion is thicker than the gate dielectric layer covering the fin structure.
13. The method for forming the semiconductor device structure as claimed in claim 12 , wherein the lower portion is thicker than the upper portion.
14. A method for forming a semiconductor device structure, comprising: providing a substrate and an insulating layer over the substrate, wherein the substrate has a fin structure, and the insulating layer has a trench extending across and partially exposing the fin structure; forming a gate dielectric layer in the trench, wherein the gate dielectric layer covers an inner wall of the trench and the fin structure; depositing a mask material layer over the gate dielectric layer; performing an oxidation process over the mask material layer to oxidize the mask material layer, wherein during the oxidation process, a first oxidation rate of the mask material layer over the inner wall is greater than a second oxidation rate of the mask material layer over the fin structure; removing the mask material layer, which is oxidized, wherein the mask material layer, which is not oxidized, is remained over the gate dielectric layer covering the fin structure and forms a mask layer; removing the gate dielectric layer over the inner wall; removing the mask layer; and forming a gate electrode in the trench and over the gate dielectric layer.
15. The method for forming the semiconductor device structure as claimed in claim 14 , wherein a topmost surface of the gate dielectric layer is between the mask layer and the fin structure after removing the gate dielectric layer over the inner wall.
16. The method for forming the semiconductor device structure as claimed in claim 14 , wherein the mask material layer, which is oxidized, over the inner wall is thicker than the mask material layer, which is oxidized, over the fin structure.
17. The method for forming the semiconductor device structure as claimed in claim 14 , wherein the mask material layer, which is oxidized, over a top surface of the insulating layer is thicker than the mask material layer, which is oxidized, over the fin structure.
18. The method for forming the semiconductor device structure as claimed in claim 14 , wherein the mask layer is thicker than the gate dielectric layer covering the fin structure.
19. The method for forming the semiconductor device structure as claimed in claim 14 , wherein the mask material layer is made of a metal nitride material.
20. The method for forming the semiconductor device structure as claimed in claim 14 , wherein the gate dielectric layer has a first dielectric constant greater than a second dielectric constant of silicon dioxide.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
February 26, 2019
December 15, 2020
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